Electric clock drive



July so, 1957 Filed Aug. 3, 1953 P. R. CONTANT ELECTRIC CLOCK DRIVE 2Sheets-Sheet l INVENTOR. Pefer R. Confam Attorney July 30, 1957 P. R.CONTANT ELECTRIC CLOCK DRIVE Filed Aug. .3. 1953 2 Sheets-Sheet 2 a ii36 a 38 ts- T: z 41 IN? LLll 'l" L: l\ii d| lL LUl- Fig. 4

. INVENTOR. Pe fer R. Confant Attorney United States Patent ELECTRICCLOCK DRIVE Peter R. Contant, Rochester, N. Y., assignor to GeneralMotors Corporation, Detroit, Mich., a corporation of DelawareApplication August 3, 1953, Serial No. 371,821

3 Claims. (Cl. 74-142) The present invention pertains to mechanism forconverting oscillatory movement into rotary movement, and moreparticularly to an electric clock drive wherein oscillatory movements ofan armature are converted into rotary motion of a clock gear traindriving member.

Heretofore, the driving mechanism between an oscillatable, magneticallyoperated armature and the rotatable driving member of a clock gear trainhas been subject to failure by reason of being subjected to excessivelyhigh unit area pressures. This invention obviates the concentration ofhigh unit area pressures on the driving connection, and, hence,materially reduces the possibility of failure. Accordingly, among myobjects are the provisions of a driving mechanism of the type comprisinga drive pawl and ratchet arrangement including means for reducing thestress imposed on the drive pawl; the further provision of a drivingmechanism wherein the drive pawl is operatively connected to anoscillatable armature through a self-aligningdrive pin connection; andthe still further provision of a driving mechanism wherein the drivepawl has a relatively large contact area with the self-aligning drivepin to which it is operatively connected.

The aforementioned and other objects are accomplished in the presentinvention by forming a loop in one end of the wire drive pawl, whichloop is received in an annular groove of the oscillatable, armaturecarried drive pin. Specifically, the present invention relates to animproved driving mechanism of the general type disclosed in Patent No.2,572,989, Contant et al., in which one end of the wire drive pawl isreceived in a small wire loop carried by the oscillatable armature of anelectric clock constructed generally according to the disclosure ofPatent No. 2,642,714, Contant et al. It has been observed that the wireloop connection between the oscillatable armature and the end of thewire drive pawl does not provide a completely satisfactory drivingconnection inasmuch as wire drive pawls are of varying cross sectionsand are oftentimes subject to wear, which may result in failure.Moreover, due to the fact that the area of contact between the wire loopand the wire drive pawl in the driving mechanism of Patent No.2,572,989, is relatively small, the unit area pressures to which thisconnection is subjected are extremely high.

In this invention, one end of the wire drive pawl is formed into a loop,which is received in an annular groove of a nylon drive pin. As nylon, asynthetic linear polyamide, has proven itself to be an excellent,self-lubricating, bearing material, and the area of contact between thewire drive pawl and the pin is relatively large, the tend- 'ency offailure in the driving mechanism at this connection is materiallyreduced. The nylon drive pin is attached to the oscillatable armature bymeans of a link member having a flanged opening, which receives apartially spherical head of the pin, thereby providing a selfaligninginterconnection between the pin and the armature and further reducingthe stress imposed on the drive pawl during armature oscillation.

The other end of the drive pawl is attached to supporting structure, andan intermediate portion thereof is spring biased so as to return thearmture to its normal position when an electromagnet associatedtherewith is deenergized. The drive pawl engages a ratchet wheel andconstitutes the means for converting oscillation of the armature intointermittent rotation of the ratchet wheel, which is then transmitted tothe driving member of the clock gear train. The driving mechanism alsoincludes a holding pawl, or a detent wire, for preventing retrogrademovement of the ratchet wheel during the return stroke of the armatureunder spring bias.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

Fig. 1 is a bottom plan view of an electric clock, with a portion of theback cut away to show the present driving mechanism.

Fig. 2 is an enlarged fragmentary view, in elevation, with certain partscut away, taken in the direction of arrow 2 in Fig. 1, with theelectromagnet deenergized.

Fig. 3 is a view similar to Fig. 2, with the electromagnet energized.

Fig. 4 is an enlarged fragmentary view, in elevation, taken in thedirection of arrow 4 in Fig. 1.

Fig. 5 is a view, in perspective, of the nylon drive pin.

Fig. 6 is a view, in perspective, of the armature link in which thedrive pin is self-aligning.

It is to be understood that although the instant driving mechanism isshown in conjunction with an electric clock, some features of thedriving mechanism, to be described, are of general application and maybe employed in diverse mechanisms where it is necessary to convertoscillatory movement into intermittent rotary movement. Asaforementioned, the driving mechanism may be associated with an electricclock of the type shown in Patent No. 2,642,714, wherein a singleelectromagnet is provided with poles associated with a timing mechanismincluding a balance wheel armature which controls and is sustained inoscillation by the intermittent energization of the electromagnet. Theelectromagnet includes a second set of poles associated with a drivingmechanism including an oscillatable index armature, which is adapted tooperate the clock gear train by means of the driving mechanism of thisinvention.

With particular reference to Fig. 1 of the drawings, the clockconstruction will not be described in detail since it is not believednecessary to understand the instant invention. The clock constructionmay include a base plate, or frame, 10 to which an electromagnet 12 isattached. The electromagnet 12 is provided with upper and lower polepieces, only one, 14, of which is shown in Fig. 1, the faces of whichare located adjacent the periphery of a balance wheel 16. As is morefully shown and described in Patent No. 2,642,714, a switch mechanism,including a contact on the staff of the balance wheel 16, engages acontact arm, not shown, during oscillatory movement of the balance wheel16, which switch mechanism is employed to control the intermittentenergization of the winding of electromagnet 12 to thereby impartperiodic magnetic impulses to the balance wheel to sustain it inoscillation.

The electromagnet 12 is also provided with a second set of upper andlower pole pieces 18 and 20. The pole pieces 18 and 20 extend generallyparallel to one another and terminate in spaced ends adapted to impartperiodic magnetic impulses to a driving armature 22.

The pole pieces 18 and 20 are interconnected by a pair of spaced bearingplates 24 and 26, which are staked thereto, as at '28 and 30. Thedriving armature 22 is drivingly connected to a worm 36. The worm 36 isI formed on a shaft 38, which is supported by a bracket 40 mounted onthe base plate, or frame, 10. The worm 36 meshes with a worm wheel 42that is drivingly connected to a clock gear train, not shown, in amanner well known in the art.

As is seen in Fig. 1, the bracket 40 is attached to the frame by meansof a pillar, or post, 44. As is further seen in Fig. 1, pole piece 14 ofthe electromagnet 12 is attached at one end of a pillar 46 from which abridge assembly 48 extends across the upper portion of the clock and bywhich the balance wheel staff, not shown, is supported for rotation. vThe means for imparting rotation 'to the ratchet wheel 34 uponoscillation of the armature 22 includes a wire drive pawl 50 and ahairpin, or U-shaped holding pawl, or detent wire 52. One end of thedrive pawl 50 is attached to the bridge assembly 48, and an intermediateportion of the drive pawl 50 is connected by a helically wound spring 54to the bracket 40.

The free end of the drive pawl 50 is formed in a loop and extendsthrough a vertical slot 56 in the bearing plate 24. The loop of thedrive pawl 50 is received in an annular groove 57 of a nylon drive pin58.

As is seen particularly in Figs. 2, 3 and 5, the drive pin 58 is formedwith a partially spherical head portion 60, which is received by aflanged opening in a link 62. The partially spherical head 60 of thedrive pin 58 provides a self-aligning connection for the pin duringarmature oscillation, and thereby minimizes stressing of the pawl 50.The link 62 is attached to the U-shaped driving armature 22 by anysuitable means, not shown, such that upon oscillation of the armature22, due to energization of the winding of electromagnet 12, lateralmovement will be imparted to the drive pawl 50. As is shown in Fig. 6,the link 62 comprises ametallic member having a flat portion 63 and anangularly extending arm portion 65 provided with a flanged opening 67for receiving the pin 58.

The holding pawl, or detent wire, 52, as aforementioned, is ofsubstantially hairpin shape, the base of which is received in an openingin the bridge assembly 48, Fig. 4. The diverging leg portions 64 and 66of the holding pawl 52 are received in a vertical slot 68 of. thebearing plate 24, the slot 68 being of such a size as to prevent lateralmovement of the leg portions 64 and 66 of the holding pawl 52. As theholding pawl 52 is formed of spring wire, it will be appreciated thattheleg portions armature in a counterclockwise direction, to theposition shown in Fig. 3, movement will be imparted to the ratchet'wheel 34 and the worm 36. Upon deenergization of the winding of theelectromagnet 12, the spring 54 through its connection with the armature22 by means of pawl will return the armature to its normal position, asdepicted in Fig. 2.

The driving mechanism operates substantially as. follows. When thewinding of electromagnet 12-is energized, the driving armature 22will'be rotated in acounterof vertical slot 56, which is preferablyformed to be only slightly larger than one tooth space of the ratchetwheel so that the ratchet wheel can only be advanced one tooth by thedrive pawl when the electromagnet is energized. In Fig. 3 the drive pin38 is shown in the position which it assumes when the electromagnet isenergized. During movement of the armature 22 between the positions ofFigs. 2 and 3, the partially spherical head portion of the drive pinwill adjust itself to minimize the stress imposed on the drive pawl 50.

During counterclockwise rotation of the ratchet wheel 34, the leg or endportion 66 of the detent wire, or holding pawl, 52 is forced upwardly inthe vertical slot 68 in the bearing plate 24 until it reaches the end ofa tooth face on the ratchet wheel, at which time it will drop behind thetooth to hold the ratchet wheel against rotation in a clockwisedirection. Thus, upon deenergization of the electromagnet 12, the biasof spring 54 will move the armature 22 in a clockwise direction to itsnormal position, Fig. 2, through the drive pawl and drive pinconnection. However, movement of the ratchet wheel 34 in a clockwisedirection is prevented by the holding pawl 52 in the manneraforedescribed.

From the foregoing description, it is apparent that the presentinvention provides mechanism for converting oscillatory movement of anarmature into intermittent rotary movement of a ratchet wheel which isconnected to the driving member of a clock gear train. Moreover, byforming the connection between the wire drive pawl and the drive pin inthe manner disclosed herein, a substantial contact area is providedwhich materially reduces the stress imposed upon the drive pawl duringarmature oscillation. Furthermore, the self-aligning connection with thedrive pawl with the armature assures contact of the driving pawl withthe periphery of the ratchet wheel and also reduces the stress imposedupon the interconnection between the drive pin and the drive pawl.

.While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adapted.

What is claimed is as follows:

1. In a driving mechanism having an oscillatory driving member, means toconvert the oscillatory movement of said member to intermittent rotarymovement of a driven member including a ratchet wheel on said drivenmember, a wire arm constituting a drive pawl for said ratchet wheel,said wire arm being fixed at one end and having its other end looped,said wire arm being adapted to engage said ratchet wheel adjacent itslooped end, and a self-aligning drive pin operatively connected to saiddriving member, said drive pin having an annular groove within which thelooped end of said wire arm is received whereby movement of said drivingmember in one direction will cause said arm to advance said ratchetwheel.

2. The combination set forth in claim 1 wherein said drive pin has apartially spherical head portion, and wherein the interconnectionbetween said drive pin and said driving member includes a link havingone end attached to said driving member and a flanged opening adjacentthe other end within which the partially spherical head of the drive pin.is received.

3. In a driving mechanism for electric clocks having an electromagnetadapted to be periodically energized 'and a driving armature mounted foroscillation in response to energization and deenergization of saidelectromagnet, a ratchet wheel, a wire drive pawl having a looped end,'a driving. pin operatively connected to said armature and "having anannular groove within which the looped end of said wire drive pawl isreceived, said drive pawl having a portion adjacent said looped end andin engagement with said ratchet wheel so as to be actuated by movementof said-armature in one direction when said electromagnet is energizedtoadvance'said ratchet wheel, means operatively associated with saidarmature for effecting move- .rnent thereof lathe opposite directionwhen the electromagnet is deenergized, and means operatively associatedwith the ratchet wheel for preventing reverse rotation thereof wheh thearmature is moved in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS126,052 Harrison Apr. 23, 1872 6 Hurley Sept. 25, 1877 Dock Feb. 5, 1907Best Mar. 25, 1941 Mueller et a1 Nov. 24, 1942 Contant et a1 Oct. 30,1951

